The present invention relates to a semiconductor device having a touch panel controller operable to control a touch panel, and an electronic device having a touch panel controller and a microprocessor, and a technique useful in application to e.g. a portable terminal device having an in-cell touch panel incorporated in a liquid crystal panel.
In a touch panel supporting a multipoint touch according to a mutual capacitance technique, for example, drive electrodes and detection electrodes are arranged to intersect with each other at e.g. right angles with dielectric interposed therebetween; the cross-coupling capacitance of each intersection makes a node capacitance. When a capacitance produced by a finger or hand arises in the vicinity of each node capacitance, the mutual capacitance of the node decreases by an amount corresponding to a combined capacitance attributed to the finger or hand. To detect the node capacitance which the change in mutual capacitance has been caused on, the touch panel controller sequentially activates the drive electrodes by use of pulses, integrates, as a signal, a change in voltage developed on each of the detection electrodes capacitively coupling with the drive electrodes, and acquires a signal resulting from the integration for each detection electrode as a signal corresponding to a change in mutual capacitance among the node capacitances arranged so as to form a matrix. A controller which drives a touch panel and detects signals means of the mutual capacitance technique like this has been already disclosed in, for instance, U.S. Patent Application Publication No. US 2007/0257890 A1.    PTL 1: U.S. Patent Application Publication No. US 2007/0257890 A1